Nicaragua said this week it will not attend a meeting of Central American foreign ministers Friday in Honduras, calling it a U.S.-inspired attempt to undermine the Contadora peace negotiations.

The governing Sandinista Front, in a surprise announcement Sept. 21, said it would sign the latest draft of the Contadora peace agreement "without modification" and urged that the United States be asked to sign as well.

U.S. officials and leaders of other Central American countries, particularly Honduras, insist that sections of the draft, especially those dealing with reductions of arms and foreign military advisers, be better defined before anyone signs.

The meeting in Honduras is expected to address those recommended changes. Vice Foreign Minister Victor Tinoco said Tuesday that Nicaragua prefers a summit meeting soon of Central American and Contadora countries.

Sandinista officials say that reopening discussions in Honduras could delay signing of an accord, if not to collapse of the effort aimed at ending regional conflicts.

The Sandinistas accuse the United States of trying to torpedo the Contadora treaty because it would result in the end of U.S. military presence in Central America.

"This is a Latin American solution to a Latin American problem, and the United States just won't buy that," said Alejandro Bendana, first secretary of the Nicaraguan Foreign Ministry.

The foreign ministers of the Contadora countries -- Mexico, Panama, Venezuela and Colombia -- said this week in Madrid that they will accept changes in the draft, but not ones that seriously affect the balance of interests struck in the document.

Sandinista officials have said they will discuss changes if other Central American countries insist, but they are pessimistic about the outcome.

Honduras has published a list of 12 specific adjustments it would make in the Contadora draft, including a stipulation that limits on the size of armies and the quantity of arms belonging to each country be set before the act is signed. The present draft calls for a commission from disinterested countries to set those limits after the signing.

The Sandinistas say they favor the current draft because it calls first for an end to attacks by U.S.-funded rebels against their government and because they will not know what quantity of arms they will need until they are sure the attacks have ended. "There is no guarantee that the United States will adhere to the Contadora agreement," Bendana said.

Other observers say there are reasons to make changes. "It is true that nobody ever expected the Sandinistas to sign it, and that no one was very careful about what actually went into it. That was a mistake," said one western envoy.

U.S. officials have said the act would cause Honduras and Costa Rica to disarm anti-Sandinista rebels and move them away from Nicaraguan borders before the Sandinistas would have to do anything.

They have also alleged a lack of effective mechanisms to verify compliance with provisions that require a reduction of arms and military advisers and an end to clandestine arms trafficking.

One western diplomat said he expected recommendations in Honduras to stress verification and to be a test of Nicaraguan sincerity.